Transcript for High Speed Chase From White House to Capitol Hill Ends With Suspect Dead

We begin with those 38 minutes of fear and chaos in the nation's capitol today. Tonight we know that the person at the center was a woman with a very young child in a car. She rammed the barricade outside the white house, next a car chase, gunshots and nervous city in lockdown. Police rushing in. A sniper in position on the senate steps. So who was this woman and what really happened? Our team was there when the shots rang out and abc's jim avila starts us off. Reporter: The unmistakable sound of gunfire as an unarmed woman sources say had a history of mental illness and a toddler in her back seat alludes police. Taking secret service and capitol hill officers on a wild mile and a half ride around d.C. Monuments and up america's most important street, pennsylvania avenue. It started here at 2:18, the southeast corner of the white house compound. The black car ramps into a barricade that do their job. Eye witnesses say uniformed secret service acts are watching it all. The barricade fell down because they were plowing through. At that point secret service was getting more reactive like whoa, whoa, trying to stop them. Then they took off after they took the barricade down. Reporter: Secret service begin the chase right up pennsylvania avenue to the f of capitol hill. By 2:40 she stops. Look against as she's surrounded by police, guns drawn. A patrol car tries to block her but she puts it in reverse and speeds away. That's when the first gunshots are fired at the fleeing vehicle. It was a two-door, dark coupe it looked like to me. I heard the gunshots and then the car tore out of the area back towards this direction with the police car following. Reporter: The tv cameraman an arabic speaker, follows her as she circles in front of the capital and buzzes up constitution avenue. Only then is she out of range and is finally stopped just past the senate side of the capitol, a block from the supreme court at about 2:45. Then members of congress walking towards their offices on a perfect fall day begin hearing a new round of gunfire. They are told to hide their identities. A police officer ran towards me and said are you a member of congress. I said yes I am and he said let me see your identification. I pulled out my identification. He said take your pin off. We wear these little pins around. He told me to take the pin off because he said you could be a targ target. Reporter: Inside the capitol members of congress have been told via loud speakers to shelter in place. We thought we heard shots, saw a lot of police cars, then we heard shots. Then the police told us to go back. We were simply walking back to our office. We heard pops, it sounded like shots. Reporter: The shots they heard came from police surrounding the black car. The suspect is fatally shot without leaving her driver's seat. The only law enforcement officer hurt is a capitol police officer who joined the pursuit and hit a capitol barricade as it was being raised to lock down the area. Late this afternoon the house said it's thanks. If I could, madam speaker ask for a moment of silent prayer for those officers who have been injured today. Reporter: Now police say that this was not an act of terrorism. Another interesting note, all those police officers who were working today because of the government shutdown, they were not being paid. Diane? All right, jim. Thank you. We want to turn to abc's senior justice correspondent pierre thomas. What have you been learning from your sources tonight. Reporter: Police are descending on the home of a 34-year-old woman in stamford, connecticut, they believe she's the suspect in today's incident. We have a name but we're not releasing it because police have not confirmed the identity but there is surely going to be an investigation on the use of force here. As you can see from the video, police were chasing the woman and ordered her to stop and were nearly run over. This this town that's a deadly situation. This was all the more scary because there was a 1-year-old child in the car. As far as we know that child is all right? Reporter: The child is okay. Again, no weapons were discovered that we know of. But remember the car can be considered a weapon. That's going to be the primary issue, diane, did the officers fear for their lives and the lives of others. Yes, and did that car trigger the massive response. Thank you so much, pierre thomas.

This transcript has been automatically generated and may not be 100% accurate.

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